Per publish 100 notes:
Pet AI: Necromancy/Necromage no longer casts Corpse Skin if pet’s damage type is physical or cold.
As most animals who have or can train Necromancy/Necromage are split spec I inquired to Bleak on how this works.
Per Bleak, if a split damage type animal has a majority Physical or Cold damage type, they will no longer cast Corpse Skin.
What about if an animal was tied Physical and something else. Then that animal would not cast corpse skin, Physical damage takes priority.
So to examine some common necro animals:
| Animal | Damage Spread | Will it cast corpse skin? |
|---|---|---|
| Shadow Wyrm | 75 Phys, 25 Cold | No |
| Nightmare | 40 Phys, 40 Fire, 20 Energy | No |
| Dread Spider | 20 Phys, 80 Poison | Yes |
| Ossein Ram | 50 Phys, 25 Cold, 25 Energy | No |
| Tsuki Wolf | 90 Phys, 5 Cold, 5 Energy | No |
| Hellhound | 20 Phys, 80 Fire | Yes |
| Pred Hell Cat | 75 Phys, 25 Fire | No |
| Dire Wolf | 100 Phys | No |
So the intention of this change is to keep Necromancy pets from nerfing their own dps while they fight, and with the way the current rules are set up that is what this will achieve.
As of 06/21/18 there was still an issue on test center that Necromancy (not Necromage) pets were still casting corpseskin. Hopefully this will be resolved before the patch hits the rest of the production shards.